Hydraulic pump



March 29, 1949.

O. W. BONNAFE HYDRAULIC PUMP 2 Sheets-Sheet 1 Filed 001'.. 23, 1944 INVENTOR. UAH/R h 50m/waff eff-Mfg March 29, 1949.

O. W. BQNNAFEl HYDRAULIC PUMP Filed Oct. 23, 1944 2 Sheets-Sheet 2 mw mm WM, 15 ,m

Patented Mar. 29, 1949 UNITED STATES' vPAI'IEINI OFFICE HYDRAULIC PUMP Oliver. W. Bonnafe, Hudson, Mass., assignor to The Lapointe Machine Tool Company, Hudson, Mass., a corporation of'Maine Application October 23, 1944, Serial No. 560,060

2 Claims. l

This invention relates to a variable delivery hydraulic pump of the type in which an annular series of cylinders in a rotating cylinder block successively discharge liquid under pressure to a recessed fixed delivery member or stator, and in which the movements of the pistons are produced and controlled by a transmission plate mounted to rotate in an angularly adjustable or tiltable cradle. Such a pump is shown for instance in the prior patent to West No. 1,722,832,nissued July 30, i929.'

It is the general object of my invention to improve the design and construction of a pump of the above-dened type, to the intent that more eiiclent operation and longer life may tained.

To the accomplishment of this general object, important features of the invention relate to the provision of an improved driving connection between the main drive shaft and the tiltable transmission plate; to the provision of improved supporting bearings for the cylinder block or rotor, and to the provision of improved valve means for the miaou-which valve means is additional to and independent of the supporting bearings.

My invention further relates to arrangements and combinations of parts which will behereinafter described and more particularly pointed out in the appended claims.

A preferred form of the invention is shown in the drawings, in which be at- Fig. 1 is a sectional side elevation of my imy proved pump;

Figl 2 is a sectional end elevation, taken along the irregular line 2-2 in Fig. V1;

Fig. 3 is a sectional end elevation, taken along the line 3 3 in Fig. l;

Fig. 4 is a detail sectional view of a universal driving connection, taken along the line 4-4 in Fig. 1; and y Fig. 5 is a sectional end elevation, taken along the line 5-5 in Fig. 1.

y Referring to the drawings, myimproved pump comprises a iixed casing or supporting frame C having a middle portion I and end plates I I and I2. A main driving shaft I4 is rotatably supported in a thrust bearing I mounted in the end plate II. The inner end of the shaft I4 is supported by a ball bearing I6 mounted at the inner end of a xed delivery member or stator II, which in turn is rigidly supported in the opposite end plate I2. The shaft I4 is continuously rotated from any convenient source of power through any usual driving connection, such as a gear or pulley (not shown).

` by a washer 28 and clamping screw 29.

A cylinder block or rotor is mounted concentric with the stator I'I andis supported at its outer end by a roller thrust bearing 22. AtA its inner end, it is provided with a ring race 23 rotatable in iixed segmental bearing members 24 (Fig. 3). The rotor 20 is thus rotatably supported free from and independent of the stator I'I but concentric therewith. The rotor 20 is fast to the inner end of the drive shaft I4 and rotates therewith. l

The rotor 2U is provided with an annular series of cylinder openings 26, each having a lining sleeve or bushing 2I held from axial displacement The washers '28 also hold the ring race 23 from displacement. Each cylinderA opening 26 is connected by an arc-shaped passage 30 to a peripheral port 3| (Fig. 2) adjacent the stator II.

A piston is slidably mounted in each cylinder bushing 21 and is reciprocated by a piston rod 36 having a swivel connection at one end to the piston 35 and a swivel connection at the opposite end to a transmission plate 40,

The plate 40 is supported by an inner roller thrust bearing 42 and an outer roller thrust bearing 43, `both of which are mounted in a tiltable cradle 44. The cradle 44 is not rotatable with the drive shaft I4 and rotor 20 but may be tilted on horizontal bearings 45 (Fig. l) perpendicular to the axis of the shaft I4 by a rotating pinion 46 which engages segment gear teeth 41 on the periphery of the cradle.

Any convenient device may be provided for turning the pinion 46 and thus varying the posihtion of the cradle 44,` and such device may be either manually or automatically operated. Such a device is shown in the West patent above referred to. Stops 48 limit movement of the cradle 44 'in both directions. l

It will be particularly noted that the outer bearing 43 for the transmission plate 40 is at a substantially greater distance from the axis of the drive shaft I4 thanthe swivel bearings for the piston rods 36, while the inner bearing 42 is at a substantially less distance. Consequently, the line of thrust of the piston rods is between the inner and outer bearings and is thus rmly supported and resisted.

The connection of the transmission plate 40 to the drive shaft I4 is best shownv in Figs. l and 4 and comprises trunnions 5I! mounted in a ring 5I xed in the plate 40. Each trunnion 50 extendsinto a roller bearing 53 mounted in a hollow rectangular transmitting member or cage 54. A

cross shaft 56 is mounted in an enlarged rectangular portion 51 of the drive shaft I4 and extends into additional roller bearings 56 also mounted in the rectangular member or cage 54. The sides of the cage 54 adjacent the bearings 58 slidably engage the sides of the portion 51 of the drive shaft, while the sides of the cage adjacent the bearings 53 have substantial clearance with respect to the portion 51 of the drive shaft, as clearly shownin Fig. l.

The cage 54 is thus free to rock on the cross shaft 56 about an axis perpendicular to the axis of the drive shaft I4, and the ring I and transmission plate 40 are free to rock about the axis of the trunnions 59, which axis is at all ltimes perpendicular to the axis of the cross shaft 56. A strong and effective universal driving connection is thus provided between the drive Shaft Il .and the transmission plate 40. As has been is supplied to the passage 6l through an entrance I passage 63 (Fig. 5) and the liquid delivered under pressure by the pump is discharged through the v passage 64.

The pump is, however, reversible, depending on the angular position of the cradle 44 and transmission plate 40, and consequently the passages 64 and 62 may supply the liquid and .the passages 6l and 63 may act as discharge or delivery passages, if the direction of rotation is reversed. Partialv cr'oss varies 65 reenforce the stator and assist in uniform distribution of the liquid to the ports 3| which are acting as intake.

Valve blocks or wipers 10 (Fig. 2) are mounted rotation of said plate, andn means to synchroto the details herein diseased. otherwise than as set forth in the claims, but what I claim is:

f 1. In a `variabledelivery hydraulic `pump comprising a stator, a cylinder block rotatable concentric therewith and having` an annular series of axially elongated cylinders therein, with a port for each cylinder successively and alternately coacting with separate intake and delivery passages in said stator, pistons in said cylinders connected to and reciprocated by a tiltable rotated transmission plate, means to tilt the plane of nously rotate said transmission plate and cylinderv block, that improvement which consists in f providing driving means for the tiltable transmission plate which comprises a drive shaft, and a universal driving connection between said shaft and said plate which has a cross shaft fixed in said drive shaft, a rectangular hollow cage mounted to rock on said cross shaft and to rotate with said drive shaft, and trunnions iixed in said transmission plate and projected into bearings in said cage which are located on an axis perpendicular to the axis of said cross shaft.

2. In a variable delivery hydraulic pump comprising a stator, a cylinder block rotatable concentric therewith and having an annular series of axially elongated cylinders therein, with a port for each cylinder successively and alternately coacting with separate intake and delivery passages in said stator, pistons in said cylinders connected to andl reciprocated by a tiltable rotated transmission plate, means to tilt the plane of in the enlarged outer ends of the partition`60 and i Y becomes worn, these blocks may be easily removed and replaced at comparatively slight expense. 'l

Two pairs of packingA rings 1| (Fig. 1) are preferably provided in the stator I1 to engage the cylindrical inner surface of the rotor 20. vThe inner rings 'il engage the abutting ends of the valve blocks or wipers 10. 'I'he rings 'Il prevent axial leakage between the stator l1 and rotor 20.

The operation of this general type of pump is well known and is fully explained in the West patent previously referred to. v

Further description thereof is considered unnecessary.

Having thus described my invention and the advantages thereof, I do not wish to be limited 70 244,631

rotation of said plate, and means 'to synchronously rotate said transmission plate and cylinder block, that improvement which comprises providing separate spaced valve blocks in said stator positioned to slidably engage the internal cylindrical port surface of said cylinder block, said valve blocks being approximately equal in circumferential width to the circumferential length of a cylinder port and to the distance between adjacent ports, and in providing packing rings in said stator to engage the inner surface of said cylinder block adjacent both ends of said valve blocks, whereby axial leakage is substantially avoided.

' OLIVER W. BONNAFE.

REFERENCES CITED The following references are of record in the le of this patent:

. UNITED STATES PATENTS Number Great Britain Dec. 24, 1925 l 

